To determine the overall surgical outcomes of infranotch T4b oral cancers and compare them with T4a oral cancers. PubMed, EMBASE and Cochrane databases from 2000 to 2022 were systematically searched. Clinical studies reporting at least one outcome following curative surgery and adjuvant therapy for comparison of patients with either infranotch T4b (IN-T4b) or T4a tumour. The heterogeneity of the included studies was determined using Tau-squared, Chi-squared, and the Higgins I2 test. The random effects model was used to determine the log odds ratio (logOR). The systematic review comprised 11,790 patients from 16 included studies. Seven studies were included in the meta-analysis (n = 11,381). For IN-T4b patients, the pooled 2 and 5year overall survival (OS) were 59.3% and 53.2%, 2 and 5year disease-free survival (DFS) 57.9% and 48.4%, 2 and 5year disease-specific survival (DSS) 72% and 68%, and 2 and 5year local control (LC), 47% and 56%, respectively. There was no statistically significant difference in 2year OS [logOR = 0.28 (-0.47, 1.03), p = 0.46, confidence interval (CI) = 95%], 5year OS [logOR = 0.7 (-0.4, 1.8), p = 0.54, CI = 95%], 2year DFS [logOR = 0.22 (-0.35, 0.79), p = 0.45, CI = 95%], 5year DFS [logOR = 0.17 (-0.42, 0.77), p = 0.57, CI = 95%], 2year LC [logOR = 0.47 (-0.33, 1.26), p = 0.25, CI = 95%] and 5year LC [logOR = 0.34 (-0.31, 0.99), p = 0.31, CI = 95%] between IN-T4b and T4a oral cancers. Results of this meta-analysis suggest that IN-T4b oral cancers have similar outcomes to T4a oral cancers, which supports down-staging IN-T4b cancers to T4a cancers.